ZeroRPC is a communication layer for distributed systems. zerorpc-node is a port of the original ZeroRPC for node.js. We have full client and server support for version 3 of the protocol, and clients/servers written in the Python version can communicate transparently with those written in node.js. This project is alpha.

To install the package:

npm install zerorpc

If you get the error Package libzmq was not found, take a look at the fix for zeromq.node. If you get the error Unable to load shared library <<path to zeromq.node>>/binding.node, make sure you run ldconfig. If that still doesn't work, check out this ticket.

To create a new server:

var zerorpc = require("zerorpc");
var server = new zerorpc.Server(context);

The constructor takes in a context object with the functions to expose over RPC. Only functions that do not have a leading underscore will be exposed. Each exposed method must take in a callback as the last argument. This callback is called as callback(error, response, more) when there is a new update, where error is an error object or string, response is the new update, and more is a boolean specifying whether new updates will be available later. You can also do callback() to close a stream response, callback(response) to send a non-stream response without an error, or callback(response, more) for a response without an error.

Events:

• error - When an error occurs.

Methods:

• bind(endpoint) - Binds the server to the specified ZeroMQ endpoint.
• connect(endpoint) - Connects the server to the specified ZeroMQ endpoint.
• close() - Closes the ZeroMQ socket.

Full example:

var zerorpc = require("zerorpc");

var server = new zerorpc.Server({
    addMan: function(sentence, reply) {
        reply(sentence + ", man!");
    },

    add42: function(n, reply) {
        reply(n + 42);
    },

    iter: function(from, to, step, reply) {
        for(i=from; i<to; i+=step) {
            reply(i, true);
        }

        reply();
    }
});

server.bind("tcp://0.0.0.0:4242");

server.on("error", function(error) {
    console.error("RPC server error:", error);
});

To create a new client:

var zerorpc = require("zerorpc");
var client = new zerorpc.Client(options);

The constructor optionally takes in an options object. Allowable options:

• timeout (number) - Sets the number of seconds to wait for a response before considering the call timed out. Defaults to 30.

Events:

• error - When an error occurs.

Methods:

• bind(endpoint) - Binds the client to the specified ZeroMQ endpoint.
• connect(endpoint) - Connects the client to the specified ZeroMQ endpoint.
• close() - Closes the ZeroMQ socket.
• invoke(method, arguments..., callback) - Invokes a remote method.
  • method is the method name.
  • callback is a method to call when there is an update. This callback is called as callback(error, response, more), where error is an error object, response is the new update, and more is a boolean specifying whether new updates will be available later (i.e. whether the response is streaming).

Full example:

var zerorpc = require("zerorpc");

var client = new zerorpc.Client();
client.connect("tcp://127.0.0.1:4242");

client.on("error", function(error) {
    console.error("RPC client error:", error);
});

client.invoke("iter", 10, 20, 2, function(error, res, more) {
    if(error) {
        console.error(error);
    } else {
        console.log("UPDATE:", res);
    }

    if(!more) {
        console.log("Done.");
    }
});